• at E11.5, the medial portion at the hindlimb AER is thinner and the distal edge of the hindlimb is flattened

• at E10.5 and E11.5, BrdU incorporation indicates decreased cellular proliferation in the medial AER with subsequent loss of limb structures (medial digits), while proliferation in the underlying mesenchyme is unaffected

• at E11.5, the medial portion at the hindlimb AER is thinner and the distal edge of the hindlimb is flattened

• at E10.5 and E11.5, BrdU incorporation indicates decreased cellular proliferation in the medial AER with subsequent loss of limb structures (medial digits), while proliferation in the underlying mesenchyme is unaffected